Cars, recreational vehicles and light trucks are presently used to tow other cars or trucks and trailers which are often heavier than the towing car or light truck. Towed vehicles can weigh two or three times the weight of the towing vehicle and can change the driving characteristics of the vehicle when attached. Presently, there are systems which can be installed to aid in better controlling a towing vehicle and towed vehicle combination. These systems are designed to allow for the application of brakes on the wheels of the towed vehicles, either with or without the application of the brakes of the towing vehicle, such that the vehicles may be slowed down and/or stopped and the attitudes of the towed vehicles can be controlled to prevent fish tailing and/or jack-knifing and generally provide for the emergency application of the towed vehicle brakes in the event of separation, or loss of power, from the towing vehicle, known as a breakaway condition. It has been found, however, that the devices of the prior art cannot accurately determine braking condition due to inherent problems in their designs.
These prior art systems are divided into two categories based on the type of braking system used by the towed vehicle. In the case of towed automobiles (cars and trucks) which are equipped with their own braking systems, various types of devices which sense that the towing vehicle is braking and then manually depress the automobile's brakes pedal are available. In the case of trailers, which are generally provided with electronic braking systems, various types of trailer brake controllers which sense that the towing vehicle is braking and then send a control signal back through the towing vehicle to the electric brakes of the trailer are available.
With respect to towed automobiles, the most common types of brake assist devices generally tap into the hydraulic brakes or air brakes of the towing vehicle. The towed automobile's braking system is connected to the brake system of the towing vehicle. By connecting the towed vehicle's braking system in this manner means are provided to both provide power to the towed automobile's brakes and to cause the brakes to be activated when the towing vehicle's brakes are activated. These types of systems detect, by noting the change in the brakes of the towing vehicle, that the towing vehicle is braking and activate mechanical means that push the brake pedal down. It has been found that the control provided by this type of system is limited in that the brakes of the towed vehicle are always applied when the brakes of the towing vehicle are applied. Independent braking, i.e. braking by the towed vehicle without braking by the towing vehicle, to assist in the control of the tow situation is generally unavailable.
Such devices, as the Brake Master and the Toad Stop Vac Brake, allow for the connection of the towed automobile's braking system to the air brakes or vacuum system of a Recreational Vehicle (RV). In these systems, a brake pedal depressor, in the form of an air cylinder, is attached to the frame of the towed automobile and clamped to the brake pedal. The air cylinder is connected to the air brakes of the RV such that the air from the RV will energize the air cylinder. When the brakes of the RV are activated, air from the RV air brake system is sent to the air cylinder, and to the brake system of the towed vehicle, causing the brake pedal of the towed vehicle to be depressed. In situations where the RV has hydraulic brakes or no vacuum system, an air compressor or vacuum system must be installed in either the RV or in the towed automobile. With respect to the systems using an air compressor, a regulator must also be installed in the RV. The regulator senses the movement of the brake pedal in the RV and causes the air compressor to send an appropriate amount of air to the air cylinder, in the towed vehicle, causing the brake pedal of the towed vehicle to be depressed. These installed air systems may also provide the vacuum needed to operate the automobile's brake system.
Other towing vehicle-automobile brake system, such as the Brake Buddy, comprise basically a box with an air cylinder and a plunger which is placed into the driver area of the towed automobile. These types of devices are plugged into the cigarette lighter of the automobile, or are otherwise connected to the automobile's electrical system, while the plunger is clamped to the brake pedal of the towed automobile. Within the box, of the device, a pendulum-activated switch and an air compressor are included. When the pendulum swings so that it activates the switch, the air compressor is activated and the plunger pushes the brake pedal down. These devices are touted as being convenient in that they need only be dropped into the towed automobile, plugged in and clamped to the brake without having to be connected to the towing vehicle's brakes or other systems. The accuracy of these devices, in detecting braking situations is questionable in that unless the vehicle is traveling on a level road or running at constant velocity, the pendulum switch is subject to misidentifying the swing caused by a slope in the road or a change in velocity as a braking situation. Further, the operator of the towing vehicle has no control over this device from the towing vehicle. Any adjustments to the system must be made while both vehicles are stationary, making accurate adjustments very difficult. Also, these devices operate in vehicles that are not running and, therefore, must use great force to depress the brake pedal. In order to be effective these devices must be able to produce this amount of force quickly. Finally, the devices, which comprise means to depress the brake of an automobile without power assisted brakes, are generally bulky and heavy and are difficult to install and remove. The devices must be removed in order to operate the towed vehicle independently of the towing vehicle.
With respect to devices designed to apply the brakes of trailers, there are presently several controllers that can automatically apply the trailer's brakes to assist the driver of the towing vehicle. Since trailer brakes are generally electronically activated it has been found that means can be used to determine the degree to which the towing vehicle is slowing and translate that information so that the brakes of the trailer may be applied. These controllers generally take the form of a box, housing all of the electronics including the means to determine that the towing vehicle is braking and the degree to which it is braking, and a power amplifier to send electricity to the trailer's brakes to accomplish braking. These prior art trailer brake controller, further, generally, comprise a control panel which allows the user to manually control braking, adjust the amount of braking and provide some maintenance, such as leveling of the device. The control panel of a brake control device also generally has a light display to indicate the degree of braking power.
It has been found that these trailer brake controllers are generally too large and bulky to be installed in such a manner that the control panel can be both seen by the driver and reached by the driver. Since the controller must be accessible to the driver of the vehicle, the controllers are generally mounted under the towing vehicle's dash board so that the controls can be reached. Although such mounting allows the driver to reach the controller, it generally places the controller out of the direct sight of the driver. Further, the driver must usually take his hand from either the steering wheel or the gear shift lever of the vehicle to operate the controller. To allow the driver to see the control panel while reaching the controls, when possible, these controllers have been mounted along a vertical wall of the dash boards of some vehicles. While this allows for a better view of the controller, such mounting has generally been found to take the device out of level or cause the device to have limited brake sensing abilities.
Trailer brake controllers typically are electrically connected to the power source of the towing vehicle, to the brake lights of the towing vehicle (as a means of detecting braking) and to the brakes of the towed vehicle. In connecting a trailer brake controller, heavy gauge wires have been used to carry power from the battery to the controller and amplified power from the controller to the brakes. Typically there is a battery wire (a large positive), a large wire going to the brakes, and some slightly smaller wires for ground and for the brake light signal. These controllers effectively take power from the battery, amplify it, and apply it to the trailer's brakes. Thus relatively high current from the towing vehicle is carried from the battery of the towing vehicle through the controller and back to the towed vehicle. Heavy gauge wire has been used in these devices as power from the car battery must be taken to the cab of the towing vehicle, amplified (to provide generally 2.5 amps of power to each trailer brake) by the controller, and then taken back through the entire length of the towing vehicle to each of the towed vehicle's brakes. It has been found that the distance from the controller to the brakes of the towed vehicle is a source of resistance and loss of electrical energize
Further, in trailer brake controllers of the prior art, electrical power is continuously provided between the towing vehicle and the towed vehicle so that it can be available immediately. Thus, when a trailer is not attached to a vehicle in which a trailer brake controller has been installed, the trailer brake controller continues to provide electricity to the wires that energize the braking system providing electricity to the open hitch socket plug. This situation not only creates the hazard of electrical shock, it has also been found that the exposure of the electrically charged socket plug, of the trailer hitch, to the atmosphere causes the connectors within the plug to more rapidly oxidize adding to the electrical resistance in the system. As a result, trailers with large number of brakes often cannot be supplied with all of the power needed for braking.
Presently, the most popular types of trailer brake control devices are proportional controllers and digital controllers. Proportional controllers generally use a dynamic accelerometer in the form of a pendulum that measures the force of braking, or deceleration, in the towing vehicle and applies the towed vehicle's brakes accordingly. The pendulum, which generally swings in the plane of the axis of motion of the towing vehicle, measures force by the degree of swing, from a default position, which the application of the towing vehicle's brakes causes in the pendulum. A greater swing by the pendulum would denote a greater urgency in braking and the proportional controller responds by greater application of the brakes. Pendulum based systems lose reliability when the device is not initially leveled, loses its level, or if the device, due to road conditions, slope of the road, etc. is not correctly level at the time of use. All pendulum based devices must be maintained level in order to operate effectively. It has been found that few of these systems maintain level and often, these systems are never level, even at the time of their installation. It has also been found that mounting these controllers along a vertical wall of the dash board of the vehicle limits the swing of the pendulum to such an extent that accurate measurement of braking may be greatly compromised.
Digital controllers do not use a pendulum to measure the force of braking. Instead digital devices provide braking by sensing the amount of time that the towing vehicle's brakes are applied and applying brakes on the towed vehicle accordingly. Since the amount of time a brake is applied is indicative of the force needed to stop the vehicle, digital controllers use brake time as the means of determining the braking needs of the towed vehicle. When the driver of the towing vehicle presses the brake pedal down for a long period of time, the digital controller interprets this to indicate the need for greater braking power in the trailer. Conversely, holding the pedal down for a small amount of time is interpreted as a need for a small amount of brake force in the trailer. Digital controllers can sense the amount of braking in the towing vehicle through connection to brake components of the towing vehicle. The components, to which such sensors can be connected, include the brake lights, the brake pedal or hydraulic brake lines of the towing vehicle. When the digital controller senses that the brakes have been applied, the sensors determine the amount of braking applied and apply the brakes of the towed vehicle. This manner of acquiring braking information has been found to be unreliable as brake components can easily lose adjustment, react differently in different weather or road conditions and may not provide reproducible results each time they are read by the controller.
Digital controllers generally are provided with a component, such as a gain control knob, that enables the operator to provide a delay of generally between two and twelve seconds for the brake controller to respond to the braking of the towing vehicle. The operator may make adjustments that cause the brakes of the towed vehicle to respond in a desired manner. A delay in the towed vehicle's braking may be desired in different types of traffic and weather situations when the application of the towed vehicle's brakes in response to a quick application of the towing vehicle's brakes may be unnecessary or dangerous. It has been found however, that a delay of even two seconds in a panic stop situation with a heavy towed vehicle may be dangerous.
Both the proportional and digital controllers are generally provided with manual controls, allowing the driver to apply the towed vehicle brakes with, for example, a slide bar or lever. However, as both types of devices must generally be mounted under the dashboard, in emergency situations, manual control of braking may cause the dangerous situation of the driver removing his hands from the steering wheel or taking his eyes off of the road. Further, braking can often times be assisted by use of the vehicle's engine and transmission by downshifting. However, if the driver must reach down to control the brakes of the towed vehicle he must either take his hands off of the steering wheel of the vehicle or off of the gear shift controller.
One manufacturer of trailer brake controllers has included a joy stick device that allows the user to manually apply the trailer brakes through a wired remote control connected to one of the types of controllers described above. This device, the Hayes Wheels Micro Control HD Plus, when used with the optional “Manual Remote”, allows the operator to manually apply the trailer brakes by holding the joy stick and pressing a button. However, the device does not comprise any means for sensing the need for brakes or for providing information concerning current braking conditions to the driver. Instead it is merely a manual braking slide control similar to the manual slide controls on other prior art trailer brake controllers. Further, the driver must have the joy stick in his hand or near his hand in order to be able to use the joy stick.
In another towing vehicle-trailer braking system, the Ultima Braking System, a sensor for determining the degree to which the towing vehicle's brake pedal is depressed is provided. The sensor causes an electrical signal to be sent to the trailer brakes. The sensor comprises a displacement sensitive manual control module that is mounted to the brake arm of the towing vehicle. Braking information is sent to the display module which is mounted in a convenient location in the cab of the towing vehicle. Adjustments to the manual control module may be made using the display module. However, the display module contains no inertia activated components and no pendulum. Although a display is provided in a viewable position, the device has all of the other shortcomings discussed with respect to other prior art proportional controllers, including the need to continually synchronize the brakes of the towed and towing vehicles.
We have invented a novel brake controller which can be used with both towed trailers and towed automobiles. Our invention allows the driver of the towed vehicle to view the display panel of a controller and have access to the manual brake controls provided. In our invention, the controller accurately determines the existence of a braking situation and sends a signal to a separate power module, which may be installed in the towed vehicle, to provide drivers to supply power to the brakes of the towed vehicle as needed. Our invention allows the separate power module to be connected to the power source of the towed vehicle so that power is not lost between the front of the towing vehicle and the towed vehicle brakes.
It is therefore an object of the present invention to provide a means to mount a control apparatus comfortably in the cab of a towing vehicle so that the brakes of a towed vehicle may be controlled accurately and without the driver having to take his eyes off the road to use the controller.
It is another object of the present invention to provide a trailer brake control device that accurately measures the deceleration of the towing vehicle and translates and causes the brakes of the towed vehicle to be applied correctly.
It is a further object of the present invention to provide a trailer brake controller that has a power module mounted closer to or on the towed vehicle so that electrical energy loss, due to resistance, is lessened.
It is a further object of the present invention to provide a power module which activates the brakes of the towed vehicle only when needed such that electrical energy need not be continuously provided between the towing vehicle and the towed vehicle.
It is a further object of the present invention to provide a brake system controller that can control the brakes of a towed car or truck using means to accurately measure the deceleration of the towing vehicle, translating those measurements and applying the towed vehicle's brakes accordingly.
It is a further object to provide a brake controller for use with a towed automobile that causes the brakes of the towed automobile to be controlled accurately by means of measurement of the braking forces on the towing vehicle and by manual means.
It is a further object of the present invention to provide a control module for a brake controller that can be used on both trailer and towed automobile systems.
Other objects and advantages of the present invention will become apparent as the description proceeds.